We should import the CSS 3 Selectors test suite, it has tests, even ones we don't pass.
The test suite is hosted by the W3C http://www.w3.org/Style/CSS/Test/CSS3/Selectors/current/ and has its repository http://hg.csswg.org/test/file/8e9f2ab0a1fe/approved/selectors3
Created attachment 101015 [details]
Patch to add Test Suite and results for the mac
Landed in http://trac.webkit.org/changeset/91104.